Refer to the exhibit.
Which ds0-group option should you select to send automated number identification information on outbound calls for this digital T1 voice circuit?
C.
E&M signaling is often the preferred option for CAS because it avoids glare, it provides answer/disconnect supervision and it can receive Automatic Number Identification (ANI) with FGD and send ANI with FGD-EANA.
In other words, you can have 1 channel-group for incoming calls and 1 channel-group for outgoing calls.